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I recently bought a 1/2" 2 flute end mill bit, which fits in my table top drill press (1/2" chuck). I'm making perfectly flat bottomed holes (won't be seen in the final project) that go almost all the way through hard wood, so I can't use a forstner bit (because of the center tip). So far, the end mill bit has been working. However, I need to make a bunch of 3/4" diameter holes. That's been tedious since it means making 4-5 holes for each 3/4" hole (clamp, make hole, move a little, clamp, make hole....).

I can't seem to find an end mill bit that has a 1/2" shank but 3/4" cutting diameter. I did see this post about using a plunge router bit on a drill press though I haven't seen a router bit that looks like it'll cut a flat bottom. Also, from that post, people recommended a fast speed for the drill press, though the instructions on the press recommend slower speeds for hard wood. So I'm confused at that too.

Welcome any thoughts - thanks!

Edit: I also just ran across this cleaning router bit - could that work?

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    "Also, from that post, people recommended a fast speed for the drill press, though the instructions on it recommend slow for hard wood." Drills and routers run at very different speeds. Fast for the drill is actually below the minimum speed on many routers. – Graphus supports Monica Sep 6 '16 at 7:19
  • Great point - up to a factor of ten! Just realized that line wasn't completely clear, will edit but meant the drill press recommend slower speeds for hard wood. – Gisto Sep 6 '16 at 11:07
  • I cannot find it at the moment but I'm pretty sure there is a virtually identical question in which someone suggested grinding the tip off a Forstner bit. Otherwise your best bet is a straight or spiral router bit and template--in which case you can use a bit smaller than 3/4". – rob Sep 6 '16 at 15:37
  • Have a link handy to the router bit(s) you're thinking of? And will they fit in the drill press? – Gisto Sep 6 '16 at 17:24
  • @rob Maybe this one? – Graphus supports Monica Sep 7 '16 at 7:37
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I have used forstner bits where the the center spurs are removable for (presumably) just this sort of job.

See

http://www.finewoodworking.com/tool-guide/product-finder/mlcs-forstner-bits.aspx

and

http://www.fine-tools.com/staketen-bormax.html

I would start the hole with the spur in place, and then remove it once the hole is established. You will definitely need a drill press for this.

  • An option, if a future reader were to go with this method, is to have 2 Forstner bits - one with the spur, one without. Start all the holes with the center spurred bit, drilling to about 1/2 depth. Then swap bits and finish with the flat bottomed one. There should be more than enough depth to get the second hole lined up, and it saves mutilating multiple bits just to drill multiple holes. – FreeMan Sep 9 '16 at 15:06
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These were all great suggestions, thank you! I wound up getting this table top surface planing bottom cleaning router bit which has been great.

1) Make sure it's really clamped down tightly. 2) Take small bites, both to keep the bit cool and to clear out debris.

This worked so great I haven't tried filing down a forstner bit - when I do I'll report back.

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